To solve this problem you must apply the proccedure shown below:
1. You can use the following formula for calculate the volume:
[tex]V=(\frac{a+b}{2})(h)(l)[/tex]
Where:
[tex]a=6m\\b=12m\\h=8m\\l=3m[/tex]
2. Now, you must substitute the values above into the formula:
[tex]V=(\frac{a+b}{2})(h)(l)\\V=(\frac{6m+12m}{2})(8m)(3m)\\V=216m^{3}[/tex]
Therefore, the answer is the last option: D. 216 m³.
